Re: [PATCH 0/4] Add support for drivers to decide bridge D3 policy

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 10/25/23 04:05, Mario Limonciello wrote:
> The policy for whether PCI bridges are allowed to select D3 is dictated
> by empirical results that are enumerated into pci_bridge_d3_possible().
> 
> In Windows this behaves differently in that Windows internal policy is
> not used for devices when a power engine plugin driver provided by the
> SOC vendor is installed.  This driver is used to decide the policy in
> those cases.
> 
> This series implements a system that lets drivers register such a policy
> control as well. It isn't activated for any SOCs by default.

I must admit that I've lost track of the status of this series...

With that said patch 4/4 looks good to me and I believe that
if this series gets accepted it will be best to send 4/4
upstream together with the rest through some other tree
then the the pdx86 tree.

So here is my ack for sending a future version of patch 4/4
("platform/x86/amd: pmc: Add support for using constraints
to decide D3 policy") upstream through another subsystem tree:

Acked-by: Hans de Goede <hdegoede@redhat.com>

Regards,

Hans






> This is heavily leveraged from the work in [1]
> 
> [1] https://lore.kernel.org/platform-driver-x86/20230906184354.45846-1-mario.limonciello@amd.com/
> 
> RFC v1->PATCH v1
>  * Simplify the logic, use pci_d3cold_enable()/pci_d3cold_disable() functions
>  * Roll https://lore.kernel.org/linux-pci/20231004144731.158342-1-mario.limonciello@amd.com/ into series
>  * Updates for some typos
>  * Re-order series.  Patches 1 and 2 can potentially apply to PCI tree, 3 and 4 to platform-x86 tree.
> 
> Mario Limonciello (4):
>   PCI: Make d3cold_allowed sysfs attribute read only
>   PCI: Refresh root ports in pci_bridge_d3_update()
>   ACPI: x86: s2idle: Export symbol for fetching constraints for module
>     use
>   platform/x86/amd: pmc: Add support for using constraints to decide D3
>     policy
> 
>  Documentation/ABI/testing/sysfs-bus-pci |  4 +-
>  drivers/acpi/x86/s2idle.c               |  1 +
>  drivers/pci/pci-acpi.c                  |  2 +-
>  drivers/pci/pci-sysfs.c                 | 14 +-----
>  drivers/pci/pci.c                       | 12 ++++--
>  drivers/platform/x86/amd/pmc/pmc.c      | 57 +++++++++++++++++++++++++
>  include/linux/pci.h                     |  1 -
>  7 files changed, 72 insertions(+), 19 deletions(-)
>